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SCAFFOLD

BASED BONE-TISSUE ENGINEERING

Presented by

Usama Nadeem

Roshan Balakrishnan

Thomas Falk

Samawat Malik

KTEK0012 3D Printing and Additive Manufacturing

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    • Rigid structures that form human skeleton
    • Made of compact bone-tissue compact tissue (the hard, outer layer) and cancellous tissue (the spongy, inner layer)
    • Contain cells called osteoblasts, osteocytes, osteoclasts, proteins & minerals, nerves & blood vessels, bonemarrow, cartilage & membranes.

BACKGROUND STUDIES

BONE

The worldwide incidence of bone disorders and conditions has trended steeply upward and was expected to double by 2020

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Osteoblasts

    • Responsible for generating & repairing bones by producing protein mixtures called osteoid (collagen & other proteins)

Osteocytes

    • Mineralized osteoblasts
    • Communicate with other bone cells
    • Help to support metabolic functions within the bone

Osteoclast

    • Causes bone resorption (breaking down of bone)
    • Help remodel injured bones
    • Creates pathways for nerves & blood vessels to travel through

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BACKGROUND STUDIES

BONE

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BACKGROUND STUDIES

SCAFFOLD

    • Bone defects are usually managed by replacing lost bone with non-biological prostheses.
    • Bone Scaffold is a 3D Bio Material Structure that is used for bone reconstruction.
    • This 3D matrix allows and stimulates the attachment and proliferation of osteoinducible cells on its surfaces.

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DESIGN STAGES

FIRST PHASE

Repetitive pattern

    • + Easy manufacturing
    • + Consistent loadcalculations

Simple design

    • + Easycalculations
    • + Easy to manufacture

Complex design

    • + Possibly better for cell growth
    • + Potential to be moreresistant to loads
    • - Difficult to manufacture
    • - Design constraints harder to maintain

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    • Different pore shapes in tissue engineering
      • Studies done on optimal cell growth and assimilations for these pore shapes
    • Try unique shapes due to better cell assimilations
    • Try simple shapes due to easiermanufacture

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DESIGN STAGES

FIRST PHASE

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DESIGN STAGES

FIRST SKECTH

    • Repeating gyroid shape
    • Great flow and theory behind the shape
    • Difficult shape creation and implementation

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    • Hexagonal pores
    • Very difficult to edit due to complicated geometry
    • Non-symmetrical due to modelling error
    • Overhang 
    • Made with Creo Parametric

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DESIGN STAGES

SECOND SKECTH

UNIT CELL 2D

UNIT CELL 3D

0.05MM GAP SUPPORT BETWEEN THE MIRROR GEOMETRY FOR MORE

STRUT DIAMETER 0.025MM

0.47MM

0.47MM

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DESIGN STAGES

SECOND SKECTH

    • 0.05mm gap support between the mirror geometry
    • SubDmulti-pipe feature (0.05 mm pipe diameter)
    • Rhinoceros 7 Corporate to complete the model
    • Small model Due to Computational Power

Printing Direction

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Material extrusion which uses continuous filament for the fabrication of 3D part.

    • Scaling factor of 20 was used to enlarge the scaffold for the plastic printing with a cube of 40.0*47.7*44.8 mm3
    • Black Filament of 2.85 mm

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DESIGN STAGES

PLASTIC PRINTING

Filament used for the fabrication of the scaffold

Ultimaker 3

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    • Scaling factor of 20 was used to enlarge the scaffold for the plastic printing with a cube of 40.0*47.7*44.8 mm3
    • Top thickness: 0.72 mm
    • Bottom thickness: 0.72 mm
    • Top layers: 8
    • Bottom layers: 8
    • Build plate adhesion type: Brim

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DESIGN STAGES

PRINTING PARAMETERS

Important printing parameters:

1. Nozzle diameter: 0.2 mm

2. Printing temperature: 210 ºC

3. Printing bed temperature: 60 ºC

4. Print speed: 30 mm/s

5. Layer thickness: 0.2 mm

6. Fan speed (cooling): 100%

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DESIGN STAGES

RESULTS & ANALYSIS

Two Possible reasons

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Two Possible reasons

Does not satisfy the 45°

DESIGN STAGES

RESULTS & ANALYSIS

Need improved geometry

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Two Possible reasons

DESIGN STAGES

RESULTS & ANALYSIS

Oozing or Drooling

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Increase the withdrawal length of the filament

Increase the print head travel speed

Does not satisfy the 45°

Need improved geometry

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DESIGN STAGES

METAL PRINTING

Type 316L stainless steel

    • Traditional stainless steel plating systems have been in use for decades for fracture stabilization.
    • The most common is Type 316L stainless steel

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DESIGN STAGES

PRINTING PARAMETERS

    • Particle size: 10-45 µm
    • Mass density: 7.9 g/cm3
    • Particle shape: Spherical

Printer used: ACONITY MIDI+

    • Laser beam source specification of the printer:
    • • IPG YLR-400-AC (Ytterbium Lasers, Gaussian beam)
    • • Fiber laser
    • • 10700 nm wavelength
    • • 400 W power
    • • 80 µm spot diameter

Important printing parameters for the scaffolds:

    • Layer thickness: 30 µm
    • Laser spot size: 80 µm
    • Laser power: 150 W
    • Hatch distance: 80 µm
    • Scan speed: 800 mm/s
    • Data for the original file of a cube was of 2.0*2.4*2.3 mm3 (sample size) for LPBF.

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DESIGN STAGES

PRINTING PARAMETERS

Initial CAD Design

Final Design

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DESIGN STAGES

RESULTS & ANALYSIS

Printing Direction

Shrinkage

Sagging

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DESIGN STAGES

FURTHER SKETCH IMPROVEMENT

Top View

Isometric View

Overhand Analysis

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WHAT WE

LEARN

    • 3D Modeling of Complex Geometry
    • LPBF Defects
    • Plastic Printing Defects
    • 45° rule implementation
    • There is still too much to explore
    • There is always a room for improvement

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WHAT WAS

EASY

    • Printing
    • Analysis of Defects
    • Availability of Literature

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WHAT WAS

DIFFICULT

    • Generating CAD for complex printable geometry.
    • Following 45 ° rule.
    • Availability of Processing Power for designing.

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REFERENCES

[1] Rahmani, R., Kamboj, N., Brojan, M., Antonov, M. and Prashanth, K.G., 2022. Hybrid metal-ceramic biomaterials fabricated through powder bed fusion and powder metallurgy for improved impact resistance of craniofacial implants. Materialia, p.101465

[2] Bahraminasab, M. Challenges on optimization of 3D-printed bone scaffolds. BioMed Eng OnLine 19, 69 (2020). https://doi.org/10.1186/s12938-020-00810-2

[3] Abdulghani, Saba & Mitchell, Geoffrey. (2019). biomolecules Biomaterials for In Situ Tissue Regeneration: A Review. Biomolecules. 9. 10.3390/biom9110750.

[4] Rider, Patrick, et al. “Bioprinting of Tissue Engineering Scaffolds.” Journal of Tissue Engineering, vol. 9, no. 2041731418802090., Jan. 2018, p. 204173141880209, www.ncbi.nlm.nih.gov/pmc/articles/PMC6176532/, 10.1177/2041731418802090.

[5] Garot, Charlotte, et al. “Additive Manufacturing of Material Scaffolds for Bone Regeneration: Toward Application in the Clinics.” Advanced Functional Materials, vol. 31, no. 5, 15 Oct. 2020, p. 2006967, 10.1002/adfm.202006967. Accessed 21 Feb. 2021.

[6] Montero Sistiaga, M., Nardone, S., Hautfenne, C., & Van Humbeeck, J. (2016). Effect of heat treatment of 316L stainless steel produced by selective laser melting (SLM). In Proceedings of the 27th Annual International Solid Freeform Fabrication Symposium-An Additive Manufacturing Conference (pp. 558-565). Solid Freeform Fabrication.

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Questions

If Any